Btrfs: only retry transaction reservation once (06d5a589) · Commits · 戴 / test

I saw a lockup where we kept getting into this start transaction->commit transaction loop because of enospce. The fact is if we fail to make our reservation, we've tried _everything_ several times, so we only need to try and commit the transaction once, and if that doesn't work then we really are out of space and need to just exit. Thanks, Signed-off-by:

Josef Bacik <josef@redhat.com>

fs/btrfs/transaction.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -181,6 +181,7 @@ static struct btrfs_trans_handle start_transaction(struct btrfs_root root,
		{
		struct btrfs_trans_handle *h;
		struct btrfs_transaction *cur_trans;
		int retries = 0;
		int ret;

		if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
		@@ -224,10 +225,18 @@ again:

		if (num_items > 0) {
		ret = btrfs_trans_reserve_metadata(h, root, num_items);
		if (ret == -EAGAIN) {
		if (ret == -EAGAIN && !retries) {
		retries++;
		btrfs_commit_transaction(h, root);
		goto again;
		} else if (ret == -EAGAIN) {
		/*
		* We have already retried and got EAGAIN, so really we
		* don't have space, so set ret to -ENOSPC.
		*/
		ret = -ENOSPC;
		}

		if (ret < 0) {
		btrfs_end_transaction(h, root);
		return ERR_PTR(ret);

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